1. Field of the Invention
The present invention relates to a panel switch useful for audiovisual equipment such as videotape recorders, other recorders and television monitors, office automation equipment such as facsimiles, telephones and duplicators, and an input tablet for a position detector.
2. Description of the Related Art
Recently, audiovisual (AV) equipment such as videotape recorders or television monitors, office automation (OA) equipment such as duplicators, facsimiles, telephones and personal computers, and electric home appliance such as cooking devices and washing machines have been rapidly reformed into a state equipped with electronic intelligent mechanism accompanied with the technological progress on micro computers or ICs. In this trend, panel switches which provide excellent switching feeling during data input are preferred as input devices for these equipment.
The prior art on these panel switches are explained in the following description with reference to the drawings, FIGS. 1-3.
FIGS. 1 and 2 illustrate a known panel switch. FIG. 1 is a perspective view of the panel switch in a disassembled state, while FIG. 2 is a side sectional view of the panel switch.
In FIG. 1, reference numeral 1 is a substrate board on which a flexible pattern circuit (hereinafter referred to as "FPC") is mounted. An insulating spacer 4 is mounted on the FPC 2 for insulating a pattern on the FPC 2 from diaphragms 3. Another spacer 5 for defining the position of the diaphragms 3 is further mounted on the insulating spacer 4. The diaphragms 3 are inserted into openings 6 of the spacer 5, and the FPC 2 is folded to cover the diaphragms 3. Knobs 7 are disposed on the folded FPC 2, and held with a casing 8. Thus, a panel switch with click mechanism is assembled.
With reference to FIG. 2, the operation of this panel switch is explained in the following.
By pushing down the knobs 7, the diaphragm 3 is reversed to provide click feeling, and a movable contact 9' comes in contact with a stationary contact 9 to make a short circuit therebetween for switching.
FIG. 3 is a sectional perspective view of a panel switch to be used as a known input tablet for a position detector.
This panel switch has the structure that a lower resistor 12 held with a lower FPC on a substrate board 10 is located at a position facing to an upper resistor 14 held with an upper FPC 13, a spacer 15 being held therebetween. In this panel switch, a switching position is detected from the resistances of these resistors 12, 14.
However, the known panel switch with a click mechanism afore-mentioned requires the diaphragms 3, to click feeling for every switch, which causes various problems as follows:
(1) The arrangement of the knobs 7 is restricted by the area of the diaphragms 3, so that the minimum pitches between the knobs 7 are limited to 7-8 mm in the known panel switch. Consequently, there are a lot of restrictions on the design of the panel switch, and it is impossible to form the panel switch into a small size.
(2) The same number of diaphragms 3 as that of the knobs 7 are required. In case of manufacturing a panel switch in which a lot of knobs are incorporated, the number of parts such as the diaphragms 3 as well as the numbers of manufacturing steps become large. As a result, the product becomes expensive.
(3) As for the input tablet for the position detector as afore-mentioned, it is impossible to incorporate an additional click mechanism in view of its structure. Therefore, it is difficult to confirm whether input operation is performed or not.